1. Field of the Invention
The present invention relates to an optical recording medium and particularly to a method of managing the defect area and method of controlling the recording/playback operation of the optical recording medium.
2. Discussion of Related Art
An optical storage medium is generally divided into a read only memory (ROM), a write once read many (WORM) memory into which data can be written one time, and rewritable memories into which data can be written several times. Rewritable optical storage mediums, i.e. optical discs, include rewritable compact discs (CD-RW) and rewritable digital versatile discs (DVD-RW, DVD-RAM, DVD+RW).
The operations of writing and playing back data in a rewritable optical disc may be repeated. This repeated process alters the ratio of storage layers for recording data into the optical disc from the initial ratio. Thus, the optical discs lose their characteristics and generate an error during recording/playback. This degradation is indicated as a defective area at the time of formatting, recording on or playing back from an optical storage medium. Also, defective areas of a rewritable optical disc may be caused by a scratch on its surface, particles of dirt and dust, or errors during manufacture. Therefore, in order to prevent writing into or reading out of the defective area, management of such defective areas is necessary.
FIG. 1 shows a defect management area (DMA) in a lead-in area and a lead-out area of the optical disc to manage a defect area. Particularly, the data area is divided into a plurality of zones, where each zone is further divided into xe2x80x98a user areaxe2x80x99 and xe2x80x98a spare area.xe2x80x99 The user area is where data is actually written and the spare area is used when a defect occurs in the user area.
There are four DMAs in one disc, e.g. DVD-RAM, two of which exist in the lead-in area and two exist in the lead-out area. Because managing defective areas is important, the same contents are repeatedly recorded in all four DMAs to protect the data. Each DMA comprises two blocks of 32 sectors, where one block comprises 16 sectors. The first block of the DMA, called a DDS/PDL block, includes a disc definition structure (DDS) and a primary defect list (PDL). The second block of the DMA, called an SDL block, includes a secondary defect list (SDL). The PDL corresponds to a primary defect data storage and the SDL corresponds to a secondary defect data storage.
The PDL generally stores entries of defective sectors caused during the manufacture of the disc or identified when formatting a disc, namely initializing and re-initializing a disc. Each entry is composed of an entry type field and a field for a sector number corresponding to a defective sector. The SDL lists defective areas in block units, thereby storing entries of defective blocks occurring after formatting or defective blocks which could not be stored in the PDL during the formatting. Each SDL entry has a field for storing a sector number of the first sector of a block having defective sectors, a field for storing a sector number of the first sector of a block replacing the defective block, and reserved areas. Accordingly, defective areas, i.e. defective sectors or defective blocks, within the data area are replaced with normal or non-defective sectors or blocks by a slipping replacement algorithm and a linear replacement algorithm.
The slipping replacement algorithm is utilized when a defective area is recorded in the PDL. As shown in FIG. 2A, if defective sectors m and n, corresponding to sectors in the user area, are recorded in the PDL, such defective sectors are skipped to the next available good sector. By replacing the defective sectors by subsequent good sectors, data is written to a normal sector. As a result, the user area into which user data is written slips and occupies the spare area in the amount equivalent to the skipped defective sectors. For example, if two defect sectors are registered in the PDL, the user data would slip and occupy two sectors of the spare area.
The linear replacement algorithm is utilized when a defective block is recorded in the SDL or when a defective block is found during playback. As shown in FIG. 2B, if defective blocks m and n, corresponding to blocks in either the user or spare area, are recorded on the SDL, such defective blocks are replaced by normal blocks in the spare area and the data to be recorded in the defective block are recorded in an assigned spare area.
As defective areas are compensated utilizing the spare area, methods of assigning the spare area play an important role in the defective area management. Typically, the spare area may be allocated in each zone or group of the data area or may be allocated in a designated portion of the data area.
One method of allocating the spare area is to allocate the spare area at the top of the data area, as shown in FIG. 3(a). In such case, the spare area is called a Primary Spare Area. Namely, the data area excluding the primary spare area becomes the user area.
The primary spare area, assigned in an initial formatting process, is assigned when a manufacturer produces the optical disc or when a user initially formats an empty disc. A variety of sizes can be allocated for the primary spare area. For example, in order to provide a 4.7 GB(Giga byte) initial data recording capacity (i.e. initial user area) in a disc with a size of 120 mm, 26 MB (Mega Byte) may be allocated for the primary spare area. Moreover, a supplementary spare area may be additionally assigned near the bottom of the data area, as shown in FIG. 3(b), if necessary.
When a rewritable optical disc is loaded, the defect information registered in the lead-in area (or lead-out area) of the DMA is first read and recorded in a specified location of the system memory of a drive. The maximum DMA storage capacity to store the defect information in the system memory of a drive, for example 32 KB (Kilo bytes), is predetermined. Thus, DMA processing conditions are given to satisfy the predetermined DMA storage capacity. The conditions are expressed below in Equation 1, where SPDL denotes the number of sectors used for maintaining the PDL entries, SSDL denotes the number of sectors used for maintaining the SDL entries, EPDL denotes the number of PDL entries, and ESDL denotes the number of SDL entries.
xe2x80x831xe2x89xa6SPDLxe2x89xa615 (or 16)
1xe2x89xa6SSDLxe2x89xa615 (or 16)
SPDL+SSDLxe2x89xa616 sectors
SPDL=[(EPDLxc3x974+4)+2027]/2048
SSDL=[(ESDLxc3x978+24)+2027]/2048xe2x80x83xe2x80x83[Equation 1]
Referring to Equation 1, a DMA storage capacity which satisfies the conditions, 1xe2x89xa6SPDLxe2x89xa615 and 1xe2x89xa6SSDLxe2x89xa615, is 32 KB (2048*16). This is because one sector corresponds to 2048 Bytes and the number of total sectors which can be used for the PDL and SDL cannot exceed 16 sectors, i.e. SPDL+SSDLxe2x89xa616 sectors. The DMA storage capacity satisfying the conditions, 1xe2x89xa6SPDLxe2x89xa616 and 1xe2x89xa6SSDLxe2x89xa616, is 64 KB (=(2048*16)+(2048*16)) because only one condition that the PDL or SDL cannot exceed 16 sectors is present. Thus, the DMA storage capacity varies with the DMA conditions.
However, during a formatting of an optical disc, an overflow may be caused by a limited number of entries which can be registered in the PDL according to Equation 1. This is because the DMA conditions do not take into consideration the size of the spare area. In other words, advancement of technology will continuously produce an optical recording medium with greater capacity or an optical recording media with the same format but different sizes and recording capacity. This would result in a variation of the standard, size and recording capacity of the optical medium. For each variation, the size of the spare area and the DMA condition should be determined for the new optical recording medium. Nevertheless, there has been no standard for determining the size of the spare area and DMA condition.
Accordingly, an object of the present invention is to solve at least the problems and disadvantages of the related art.
An object of the present invention is to provide a method of managing the defect area of an optical recording medium in consideration of the spare area size and the DMA condition.
Another object of the present invention is to provide a method of managing the defect area of an optical recording medium by determining the DMA condition using an interrelation between the spare area size and the DMA condition.
A still another object of the present invention is to provide a method of managing the defect area of an optical recording medium by determining the size of initially assignable spare area using the interrelation between the spare area size and the DMA condition.
A further another object of the present invention is to provide an optical recording medium in which the spare area is assigned in consideration of the interrelation between the spare area size and the DMA condition.
A still further object of the present invention is to provide a method of controlling recording/playback of an optical medium, which allows recording/playback of optical media of different conditions in a single system.
A still further object of the present invention is to provide a method of controlling recording/playback of an optical medium, which allows recording/playback of 120/80 mm optical media having the same format but different sizes in a single system.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purposes of the invention, as embodied and broadly described herein, a method of managing a defect area of an optical medium includes determining the size of the initially assignable spare area; and determining a PDL entry condition such that a spare area for linear replacement is left in the initially assignable spare area after the slipping replacement during a formatting. The PDL entry condition is determined by utilizing the interrelation between the initially assignable spare area size and the PDL entry condition.
The size of the initially assignable spare area is determined based upon the initial recording capacity and the PDL entry condition. A SDL entry condition is determined using the set PDL entry condition and a predetermined maximum spare area size. The SDL entry condition may also be determined using the set PDL entry condition and a predetermined DMA storage capacity. When the predetermined maximum spare area size is larger than the initially assignable spare area size, a separate spare area is additionally assigned as required.
To accomplish the objects of the present invention, there is also provided a method of managing a defect area of an optical medium in which a PDL entry condition is determined to allow a spare area for linear replacement to exist in the initially assignable spare area after slipping replacement during a formatting.
To accomplish the objects of the present invention, there is provided an optical medium in which a spare area is assigned to allow a spare area for linear replacement to exist in the initially assignable spare area after slipping replacement during formatting. In another embodiment of the present invention, a method of controlling the recording/playback of an optical medium is provided including judging the kind of the optical medium when an optical medium is loaded, and controlling the recording/playback of the optical medium based upon a DMA condition of the judged optical medium.
Furthermore, to accomplish the objects of the present invention, there is provided a method of controlling the recording/playback of an optical medium including judging if an optical medium has a diameter of 80 mm when an optical medium is loaded, and if it is judged to be an optical medium having the diameter of 80 mm, controlling the recording/playback operation on condition such that the number of sectors managed by a PDL among a DMA condition does not exceed 11.